package state

import (
	"fmt"
	"log"
	"os"
	"path/filepath"
	"time"

	"github.com/nightlyone/lockfile"
)

const LOCk_WAIT_MILLIS = 30000

func Lock(jobFullName string, lockType string) (*lockfile.Lockfile, error) {

	fn := fmt.Sprintf("%v_%v", jobFullName, lockType)
	lock, err := lockfile.New(filepath.Join(os.TempDir(), fn))
	if err != nil {
		return nil, fmt.Errorf("Cannot init lock. reason: %v", err)
	}

	var retries = 300
	for retries > 0 {
		err = lock.TryLock()
		if err == nil {
			log.Printf("Locked via lockfile %v", lock)
			return &lock, nil
		}
		if _, ok := err.(interface{ Temporary() bool }); ok {
			retries--
			time.Sleep(time.Millisecond * 100)
		} else {
			retries = -1
		}
	}
	return nil, fmt.Errorf("Timeout acquiring lock %v/%v", jobFullName, lockType)
}

func Unlock(lock *lockfile.Lockfile) {
	if lock != nil {
		log.Printf("Unlock lockfile %v", *lock)
		lock.Unlock()
	}
}